Distribution of Dislocations in SrTiO<SUB>3</SUB> Single Crystals

Abstract

SrTiO 3 is used as a substrate for thin films of superconducting oxides. From this point of view, it is important to investigate lattice defects in as-grown or as-annealed bulk SrTiO 3 crystals. In this paper, we aimed at distribution of dislocations in SrTiO 3 single crystals under no external force. We examined two groups of crystal plates of which lapped faces were (001) and (011). We checked the defect distribution throughout the crystals by X-ray topography (reflection method). X-ray topographs showed that the (011) crystal plates had more defects than (001) plates. Then microscopic observation by transmission electron microscopy (TEM) revealed that many dislocations existed in the point where thick line image contrast was observed by X-ray topography in the (011) plate. Most of them had type Burgers vectors. On the contrary, it was showed that very few dislocations were dispersed throughout the (001) crystal plates by X-ray topography. It was revealed that these dislocations did not always exist alone and had type Burgers vectors by TEM.